Optimising Our Solar Project
The DeGrussa Solar Project is a photovoltaic (PV) solar (10 MW) and battery (1.81 MWh) system. The system was integrated within an existing diesel power station in mid-2016. During FY2019, the plant went through a series of optimisation changes to increase the ability of the solar plant to supply power to the DeGrussa grid.
The key changes were related to the solar covering ratio and mine operating spinning reserve control settings. The solar covering ratio was reduced from 100 per cent to 80 per cent, meaning that only 80 per cent of the total PV generation has to be covered by a combination of battery and diesel spinning reserve. The operating spinning reserve was reduced from 8MW to 6MW, reducing the number of diesel generating sets online from six to five.
Since the changes, we are able to produce 0.5MW of solar above the previous settings. The annual average solar power is now 57 per cent (8MW), covering 57 per cent of the total mine demand during daylight hours (50 per cent before). At peak power, the plant covers 68 per cent (9.5MW) of the total grid needs. This occurs during the summer months when irradiance is higher. In some instances, we’ve observed 9.9MW of solar penetration, covering 71 per cent of the total daylight hour needs.